摘要
为探讨我国亚热带山地常绿落叶阔叶混交林的林隙干扰特征 ,对三峡大老岭地区这一植被类型进行调查 ,分析了植被中林隙的数量、类型及成因 ;林隙形成木 (GM)的类型、数量、物种构成和径级结构 ,以及林隙和 GM的多尺度空间格局特征。结果表明 :1)林隙密度为 11.7个· hm- 2 ;冠林隙和扩展林隙分别占森林面积的 11.0 9%和 2 7.0 6 %。平均每个林窗的形成木为 4.5株 ;单株 GM形成的林隙只占 17.46 % ,其中翻倒木集群性最强。对林隙形成的贡献大小次序是 :翻倒木 >折干 >枯立 >折枝。 2 )林隙成因方面 :冬雪和春、秋冻雨的影响最大 ;病害影响其次 ;树木间的牵连和撞击扩大了林隙的范围 ;陡峭的地形增大林隙形成的机率 ;干旱的影响很小。 3) 6 8种 GM主要是森林建群种 ;常绿树种形成林隙的平均机率高于落叶种。 4)
This paper aims to explore the characteristics of gap disturbances in mixed evergreen/deciduous mountain forests in the Chinese subtropical region. Vegetation plots at Mt. Dalaoling in the Three Gorges region were analyzed according to the quantity, type and causal factors of gaps, the type, number, species composition and size structure of gap makers (GM), as well as the multi scale spatial characteristics of both gaps and GM. The results indicate that: 1) Gap density is 11.7per/hm 2 and the area of canopy gaps and extended gaps occupy 11% and 27% of the forest area respectively. The average number of GM per gap is 4.5, and only 17.46% of all gaps were created by just one GM. Uprooting treefalls were spatially most convergent relative to other types of GM. The order of contributions to gap formation is treefall>trunk snatch>standing death>branch snap. 2) Snows in winter and ice storms in early spring and later autumn play an important role in gap creation, followed in significance by attacks from disease and pests. Gap sizes were usually enlarged by the reciprocal bumping and dragging and consequently mountain topography tends to increase the frequency of gap formation. Drought has little effect on gap formation rates. 3) The dominant species chiefly constitute the GMs, which included 68 tree species in all. Evergreen trees have a larger average probability of producing gaps than deciduous trees. 4) The size structure of GM suggests that the gap disturbance is very frequent in the mountain forest.
出处
《植物生态学报》
CAS
CSCD
北大核心
2001年第3期276-282,共7页
Chinese Journal of Plant Ecology
基金
国家自然科学基金!项目 ( 3 0 0 0 0 0 2 4)
中国科学院植物研究所植被数量生态学开放实验室基金 !( L P990 8)
关键词
三峡
山地常绿落叶阔叶混交林
干扰状况
林隙特征
尺度
Mt. Dalaoling, The Three Gorges, Mixed evergreen/deciduous mountain forest, Disturbance regime, Gap properties, Scale
